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View Full Version : Reaming using removable pilot reamers, vs other methods



bingo
04-28-2011, 12:13 PM
Is the use of floating reamers considered to be a less accurate way of chambering, than some of the other methods? I have only chambered a few barrels, and did all of them by first turning the barrel between centers, then chucking it up in a four jaw at the head, and in a steady over the bed, then using a floating rougher, and finisher.
I Just read the "Jackie" thread, and that looks like a lot more work, so my guess is that is considered to be a more accurate method of aligning the chamber?

mike in co
04-28-2011, 01:24 PM
most of the accuracy is in the operator, not the method.
thru the headstock, to me, is better...easier to set up and dial in.
i use an import truset type chuck that is adjustable...the chuck is adjusted, not the jaws.
i consider the headstock bearings more "stable" than anything out on the ways.
i use removable pilot reamers without the pilots most of the time.

i consider jackie's method superior...my opinion.
consider that jackie is a machinist that learned gunsmithing.....not someone that wants to be a gunsmith, so was taught some lathe/mill operations.

and again it is more about the operator and his tools than any one method.
mike in co

bingo
04-28-2011, 09:15 PM
Thank You for the reply mike.

pdhntr
04-29-2011, 09:15 AM
Bingo,

You might want to take a long look at the thread "chucking up a barrel" started by Hal. It's not very far down the list. Lots of good information and discussion.

Jim

Charles E
04-30-2011, 06:07 AM
Is the use of floating reamers considered to be a less accurate way of chambering, than some of the other methods?

By some. Phil Bowers completely cuts the chamber with a boring bar. Most of us don't have the equipment or skill for that. Jackie probably does, but I *think* he likes to use the reamer for the finish it leaves. As far as finish and boring bars, when you get into exotic cutting tools, I have no idea of what's even available. Phil does.

As has been said soooo many times, you have to check your work when done. If it is right, it doesn't matter how you got there. So the question becomes "with such & such a technique how often do *you* get the final job right?"

Butch Lambert
04-30-2011, 03:55 PM
Charles,
The problem is a lot of folks don't know how to check their work.
Butch

bingo
05-01-2011, 12:01 AM
Thank you for the responses. After reading through some more threads, I am gaining an enhanced understanding of the factors which should be taken into account when chambering, to generate a first class job, regardless of the tooling used. I have cut some incredibly complex internal profiles by single point,
and see no reason not to do a chamber that way, except that a reamer is so easy.

JerrySharrett
05-01-2011, 06:31 AM
All this discussion about using reamer pilots, or not to use them, or use a loose ones makes me wonder if the latter two are best, why do the reamer makers even bother to make reamers that can have pilot bushings changed. Or, why do they even bother to offer bushings of different sizes???

jackie schmidt
05-01-2011, 10:05 AM
If you are not willing, or do not know how, to check your work, then you are simply assuming that your set-up is sound.

I have stated several times how to do final inspection, you can do a search and find it.

Go back and look at my thread on building my 1949 vintage Remington 721. In the pictures where I trued the threads and action face with the bolt way, I end it by showing you the inspection procedure to actually verify that I had corrected the maladies that were present. That is a true and valid inspection. Ant

It make no difference how you do things, (that is, if cost and time are of no consequence), in the end, the only thing that counts is the final product, and whether it will meet the final inspection and criteria for the job at hand.
.....jackie

http://benchrest.com/showthread.php?74022-Action-Trueness-Test-On-My-Old-Remington-721-I-Just-Bought/page7

bingo
05-01-2011, 11:25 AM
Jackie, I cannot tell you how much I appreciate your threads. Coming at this from the mechanics Perspective I share your ideals for what makes a job right.
The work should be proven to be correct. As with all things though, and regardless of the skill of the man, for those of us who do not know, we need to learn what correct is for a given job, and what are considered the best general practices for going about the work. Decisions must be made. Which method offers the best finished job, is often dictated by both the available tooling, and the skill of the operator. A less skilled man can produce an excellent result with the use of good tooling and adequate technique. A superior mechanic can accomplish the same task using more general tooling, with the advantage that a special tool need not be purchased for each job, assuming the machine tools doing the work are capable of holding tolerance.
For my first barrels, I opted for the piloted reamers, as it seemed the simplest and most efficient method of putting the correct shaped hole into a tube. Now
with some more exposure to how others are going about chambering, and gauging for correct orientation, I will "step up my game", and bring some more finesse and understanding to the process. Once again, thank you for putting the information out there.
-Bingo

kiwi smith
05-07-2011, 11:18 PM
Is the use of floating reamers considered to be a less accurate way of chambering, than some of the other methods? I have only chambered a few barrels, and did all of them by first turning the barrel between centers, then chucking it up in a four jaw at the head, and in a steady over the bed, then using a floating rougher, and finisher.
I Just read the "Jackie" thread, and that looks like a lot more work, so my guess is that is considered to be a more accurate method of aligning the chamber?

Bingo,
From my experience, chambering between centres is fine for hunting rifles and/or where the blank you are using is reasonably straight. It can also be a lot simpler, and potentially more accurate and with less risk than chambering through the headstock if you either don't have a good lathe with ultra-high precision spindle bearings, or don't have a good secure set-up for chambering that way, and the extra high degree of precision that that method requires for an accurate set-up before you even start machining on it.

FWIW, I use the reamers with the removeable pilot bushings (JGS/PTG style). Ideally, you should be able to use a bushing within 0.0002" (2 tenths) of what will just slip into the bore. If you can't chamber to full headspace depth without some degree of reamer bind or fighting, then you likely have an alignment problem, or a problem barrel blank.

If you are lacking experience, then stick to chambering between centers, and only use good quality barrels with optically straight bores. You will have less hassles that way, and likely achieve better results.

Good Luck!

Dean.

lejarretnoir
05-08-2011, 11:39 AM
I also subscribe mostly to the Jackie Schmidt technique.
Was always taught as an apprentice that reamers were used to clean up holes, not remove the bulk of the metal. Therefore I drill, bore, then ream. Saves wear and tear on the reamer. Used piloted and pilot less reamers. Reamers will follow the setup you created. If the original hole is out of true, so will be the finished reamed hole.
Even piloted reamers have some slop in the pilot or it would not turn. Most likely .0005 tolerance for fit in the bore and the same for pilot on reamer. So that would add up to .001 or so play. I haven't measured it, so maybe someone could tell me different.

bingo
05-08-2011, 11:40 AM
Thank you for the response Kiwi. My manual lathe is too long through the headstock for barrel work, hence the need to work over the bed. My experience as a machinist aside, due to the specific nature of chambering barrels for accuracy, I have to go to school on the subject
lest I waste time re-inventing the wheel. I am learning that there are key factors which will effect the outcome of a chambering job, regardless of the work methods employed, and that as with most work, there is no panacea, but rather a development of understanding the factors which may contribute to the best possible finished job. Thanks to all for the help.